Presentation
Surveillance scan of a presumed benign condition.
Patient Data
Small lytic focus containing CSF intensity material involving the posterior aspect of the clivus. A small focus of CSF signal material protrudes posteriorly to the dorsal cortex of the clivus to abut the basilar artery. The lesion is just left of midline, has corticated margins on prior CT, and on previous contrast enhanced MR has never enhanced. No soft tissue component was seen. The surrounding clivus bone marrow is normal. No other abnormalities within the prepontine cistern and cerebellopontine angles.
A few hyper T2 and FLAIR signal abnormalities scattered through the supratentorial white matter are nonspecific, likely representing chronic small vessel ischemia, in a number distribution usually seen the patient's age group. Brain parenchyma is otherwise unremarkable.
Well-defined rounded and high T2 signal lesion within the mucosa of the nasopharynx in keeping with a Thornwaldt cyst.
Lesion in the clivus slightly to the left of midline measures 5 x 6 mm and is similar in appearance to the external imaging. No other bony lesions demonstrated. No intracranial mass, hemorrhage or extra-axial fluid collection. Normal grey-white matter differentiation.
Case Discussion
This case illustrates the follow-up of an asymptomatic incidental finding involving the clivus, probably representing an ecchordosis physaliphora. Histologically, this condition is indistinguishable from a chordoma, although on imaging the latter has an infiltrative growth and usually are symptomatic.
The diagnosis was presumed based only on imaging characteristics.